① The role and source of organic fertilizers
Organic fertilizers are derived from fermented and decomposed products of various animals and plants, including rapeseed cakes that have been processed by special processes. They are odorless and rich in biological substances, animal and plant residues, excrement and biological waste. This kind of fertilizer can provide comprehensive and balanced nutrition for crops, and its fertilizer effect is long-lasting. It can not only increase and renew organic matter in the soil, but also stimulate the growth of microorganisms, thereby improving the physical, chemical properties and biological activity of the soil. It can be said that organic fertilizer is an important nutrient source that is indispensable for the production of green food.
Compost is an organic fertilizer made by mixing various orange stalks, fallen leaves, grass, animal and plant residues, and human and animal feces with a small amount of soil and then piling and fermenting. The process of composting is similar to composting, except that it is fermented under flooding conditions. Stable manure is a fertilizer made by composting the feces and urine of livestock and poultry such as pigs, cattle, horses, sheep, chickens, and ducks with straw bedding. Biogas fertilizer is the byproduct of biogas produced by the decomposition of organic matter in a sealed biogas tank, including biogas liquid and residue. Green manure uses cultivated or wild green plants as fertilizer, such as mung beans and broad beans of the legume family, as well as ryegrass and radish of non-legume family. In addition, crop straw, cake fertilizer and mud fertilizer are also important sources of organic fertilizer.
② Development trend of biological organic fertilizer
With the advancement of science and technology, through artificial pure cultivation of beneficial bacteria, combined with scientific refining technology, a variety of different varieties of biological organic fertilizer can be produced. This type of fertilizer can not only improve soil quality, but also reduce environmental pollution and improve fertilization effect.
In developed countries abroad, organic agriculture has been widely praised. These countries generally oppose the use of chemical fertilizers and prefer to use organic fertilizers. They believe that the use of chemical fertilizers will lead to environmental pollution, soil fertility decline, aggravate soil erosion and increase energy consumption. But for permanent fruit trees, the application of chemical fertilizers is necessary, because the mineral nutrients absorbed by fruit trees must be in inorganic form to be used.
③ Fertilizer use and environmental impact
When the mineral elements from the decomposition of organic matter in the soil and the mineral elements obtained from rocks, soil, air and rainwater cannot meet the needs of fruit trees to continuously improve the yield and quality, the appropriate amount of fertilizer becomes a necessary bionic cultivation measure.
In response to the soil environmental pollution problems that may be caused by the application of fertilizers, we need to take a series of measures. First, we must control the excessive application of certain elements. For example, excessive use of nitrate nitrogen will produce NO2-, which can be solved by adjusting the application amount or improving the soil structure.
④ Types and applications of compound fertilizers
Compound fertilizers, as a form of efficient fertilizer, have the characteristics of high nutrient content, few by-components and excellent physical properties. They are of great significance for balanced fertilization, improving fertilizer utilization and promoting high and stable yields of crops.
At present, the development of compound fertilizers presents three major trends. The first is multi-variety specialization, that is, developing different special fertilizers for different crops to meet their specific fertilizer absorption needs. The second is multi-functional medicinalization, that is, combining pesticides with fertilizers to simplify the steps of mixing pesticides with seeds. Finally, there is high-concentration and long-term compound fertilizer. This type of compound fertilizer reduces the number of fertilization times due to its high concentration and long-term effect.
However, although compound fertilizer is good, it cannot completely replace other fertilizers. When conditions permit, the application of decomposed organic fertilizer should be increased appropriately. The combined use of organic fertilizer and compound fertilizer not only helps to improve fertilizer efficiency and nutrient utilization, but also improves the soil, activates beneficial microorganisms in the soil, and provides more comprehensive nutrition for crops.
